Semiconductor wafer processing apparatus

ABSTRACT

A processor for processing articles, such as semiconductor wafers, in a substantially clean atmosphere is set forth. The processor includes an enclosure defining a substantially enclosed clean processing chamber and at least one processing station disposed in the processing chamber. An interface section is disposed adjacent an interface end of the enclosure. The interface section includes at least one interface port through which a pod containing articles for processing are loaded or unloaded to or from the processor. The interface section is hygienically separated from the processing chamber since the interface section is generally not as clean as the highly hygienic processing chamber. An article extraction mechanism adapted to seal with the pod is employed. The mechanism is disposed to allow extraction of the articles contained within the pod into the processing chamber without exposing the articles to ambient atmospheric conditions in the interface section. The article processor also preferably includes an article insertion mechanism that is adapted to seal with a pod disposed in the interface section. The article insertion mechanism is disposed to allow insertion of the articles into the pod after processing by the at least one processing station. The article insertion mechanism allows the insertion of the articles without exposing the articles to ambient atmospheric conditions in the interface section.

BACKGROUND OF THE INVENTION

This Application is a Division of U.S. patent application Ser. No.10/180,793, filed Jun. 25, 2002 and now U.S. Pat. No. 6,599,075, whichis a Division of U.S. patent application Ser. No. 08/994,737 filed Dec.19, 1997, now U.S. Pat. No. 6,447,232, which is a Continuation-in-Partof U.S. patent application Ser. No. 08/851,480, filed May 5, 1997, nowabandoned, which is a Continuation-in-Part of U.S. patent applicationSer. No. 08/680,463, filed Jul. 15, 1996, now U.S. Pat. No. 5,664,337,which is a Continuation-in-Part of U.S. patent application Ser. No.08/622,349, filed Mar. 26, 1996, now U.S. Pat. No. 5,784,797, which is aContinuation-in-Part of each of U.S. patent application Ser. No.08/236,424, filed Apr. 28, 1994, and now U.S. Pat. No. 5,544,421; Ser.No. 08/415,927, filed Mar. 31, 1995, now U.S. Pat. No. 5,660,517; andSer. No. 08/415,240, filed Apr. 3, 1995, now U.S. Pat. No. 5,678,320.U.S. patent application Ser. No. 08/851,480, and U.S. Pat. Nos.5,784,797, 5,544,421 and 6,447,232 are incorporated herein by reference.

The present invention relates to an automated semiconductor waferprocessing apparatus that is used, for example, to execute liquid andgaseous processing of wafers. Such an apparatus can be used to processsemiconductor wafers, data disks, semiconductor substrates and similararticles requiring very low contaminant levels. More particularly, thepresent invention relates to such an apparatus having an improvedinput/output wafer handling system.

The processing of semiconductor wafers and the like has become of greateconomic significance due to the large volume of integrated circuits,data disks, and similar articles being produced. In recent years, thefeatures used in integrated circuits and data disks have decreasedsignificantly in size, thus providing greater integration and greatercapacity. In addition, the diameters of semiconductor wafers haveincreased over time, providing greater economies of scale with respectto each processed wafer.

While the apparatus and methods utilized heretofore for processingsemiconductor wafers have operated with varying degrees of success, theyhave also sometimes suffered problems with regard to contamination orparticle additions which can occur during processing. As the featuresand geometries of the discrete components formed on the semiconductordevices have become smaller and more densely packed, and as thediameters of the semiconductor wafers have increased, the need for morestringent control over contamination and breakage has become more acute.

A constant challenge in the production of semiconductors is theculmination of particle contamination. With respect to all types ofsemiconductor processors, preventing contaminant particles from enteringinto the processor enclosure is of paramount importance. Such particlescan affect the photographic processes used to transfer the integratedcircuit layouts onto the wafers being processed by causing deteriorationof the image being transferred onto the wafer. Contaminant particles mayalso result in the altering of the characteristics of the device that isbeing manufactured.

One of the greatest sources of contaminating particles is the presenceof environmental dust carried in the air surrounding the semiconductorprocessors. To reduce the amount of environmental contamination,semiconductor integrated circuit manufacturers have taken extrememeasures to provide working areas with relatively low amounts ofenvironmental dust. These areas are called “clean rooms”. Such workingareas are expensive to build and operate. It is therefore preferable tolimit the number and size of the clean rooms used to manufacture aparticular device.

Another problem associated with traditional semiconductor processorsrelates to the fact that toxic and corrosive processing fluids, such asacids, caustics, solvents and other processing fluids are used in themanufacturing process. Such processing fluids must be maintained withincontrolled processing chambers to avoid corrosion and other harmfuleffects to personnel and materials outside of the semiconductorprocessor enclosure. Of concern are both liquid and gaseous forms ofprocessing fluids, both of which should be prevented from exiting theprocessor chamber and contacting machine parts susceptible to corrosion.Thus, there exists a need to provide semiconductor processing equipmentthat adequately seals processing fluids inside the processing chamberduring manufacturing and prevents them from escaping and causing damage.

The present inventors have recognized the foregoing problems and haveaddressed solutions for them in the apparatus described herein. Theapparatus provides an improved system for batch wafer handling inautomated semiconductor process equipment. Further, the apparatusprovides a processing system which permits use of standard wafercontainers or pods. Still further, the apparatus provides a processingsystem for multiple wafer container loading wherein air infiltrationduring the loading operation is minimized while also allowing continuousautomated processing of the wafers.

In accordance with a further feature of the present apparatus, theapparatus is provided with an improved door actuating and sealingassembly that provides a fluid tight seal which prevents contaminantparticles from entering a processing chamber and prevents processingfluids and vapors from escaping from the chamber.

BRIEF SUMMARY OF THE INVENTION

A processor for processing articles, such as semiconductor wafers, in asubstantially clean atmosphere is set forth. The processor includes anenclosure defining a substantially enclosed clean processing chamber andat least one processing station disposed in the processing chamber. Aninterface section is disposed adjacent an interface end of theenclosure. The interface section includes at least one interface portthrough which a pod containing articles for processing are loaded orunloaded to or from the processor. The interface section is hygienicallyseparated from the processing chamber since the interface section isgenerally not as clean as the highly hygienic processing chamber. Anarticle extraction mechanism adapted to seal with the pod is employed.The mechanism is disposed to allow extraction of the articles containedwithin the pod into the processing chamber without exposing the articlesto ambient atmospheric conditions in the interface section. The articleprocessor also preferably includes an article insertion mechanism thatis adapted to seal with a pod disposed in the interface section. Thearticle insertion mechanism is disposed to allow insertion of thearticles into the pod after processing by the at least one processingstation. The article insertion mechanism allows the insertion of thearticles without exposing the articles to ambient atmospheric conditionsin the interface section.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a perspective view of a semiconductor processing system inaccordance with one embodiment of the invention showing the variousstations of the input/output section and the general components of theprocessing section.

FIG. 1B is a front perspective view of a semiconductor processing systemaccording to the present invention with portions broken away to betterillustrate some of the principal components thereof.

FIG. 1C is a top view of the semiconductor processing system of FIG. 1Aillustrating flow of semiconductor wafers therethrough.

FIG. 2 is a rear perspective view of the semiconductor processing systemwith some portions removed to better illustrate certain components.

FIG. 3 is a perspective view of an input/output subassembly of theprocessing system illustrated in FIG. 1.

FIG. 4 is a perspective view of a load plate used in the input/outputsubassembly.

FIG. 5a is a perspective view of a wafer container in conjunction withthe load plate and the elevator plate of the input/output subassembly.

FIG. 5b is a top view illustrating the transfer of a wafer containerfrom the elevator plate to the load plate.

FIG. 6 is a perspective view of a preferred semiconductor inventorysubassembly forming part of the processing system illustrated in FIG. 1.

FIG. 7 is a perspective view of a container transfer forming part of thedocking assembly of the processing system illustrated in FIG. 1.

FIG. 8 is a perspective view of a hatch interface forming part of thedocking subassembly of the processing system illustrated in FIG. 1.

FIG. 9a is a front perspective view of a wafer transfer comb formingpart of the transfer subassembly of the processing system illustrated inFIG. 1.

FIG. 9b is a rear perspective view of the wafer transfer combillustrated in FIG. 9a.

FIG. 10 is a perspective view of the conveyor for the wafer combillustrated in FIGS. 9a and b.

FIG. 11A is a perspective view of a wafer bunching comb forming part ofthe processing system illustrated in FIG. 1.

FIG. 11B is a cross-sectional view illustrating a groove of the comb ofFIG. 11A.

FIG. 12 is a perspective view of a semiconductor processor forming apart of the processing system illustrated in FIG. 1 and employing anovel door actuation and sealing mechanism.

FIG. 13 is a perspective view of the processor door actuation assembly.

FIG. 14 is a cross-sectional side view of the processor door in an openposition.

FIG. 15 is a cross-sectional side view of the processor door in a closedposition.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A, 1B, and 2 generally illustrate a processing system 10 whichincludes a basic frame 12 defining the walls of the processing system10. Generally stated, the processing system 10 is divided into twoprincipal sections—an interface section 14 for receiving andinventorying semiconductor articles, and a processing section 16, whichcontains one or more processing stations 3 for processing thesemiconductor articles using, for example, liquid and/or gaseousprocessing procedures.

As illustrated, the interface section 14 is preferably divided into aplurality of stations. In the disclosed embodiment, the interfacesection 14 is comprised of a container access station 5, an inventorystation 6, a container docking station 7, and a wafer transfer station8. In operation, wafer containers 51 are inserted into the processingsystem 10 through a door 32 at container access station 5. Eachcontainer 51 is then stored at the inventory station 6 until such timeas the container is accessed by the components of the container dockingstation 7. A wall 11 effectively separates the stations 5, 6, and 7,from the wafer transfer station 8. To this end, wall 11 is provided withone or more doors against which each container 51 may seal and allowdirect access of the wafers contained in the container 51 withoutcontamination by the exterior surfaces of container 51. As such, thewafers in any given container 51 may be inserted into the processingsection 16 of the processing system 10 without exposure to potentiallycontaminating environments.

With reference to FIGS. 1A and 1B, the frame 12 is constructed to forman enclosure that substantially encloses the processing systemcomponents and defines a working space 20. The semiconductor articles,such as semiconductor wafers, are held and maneuvered within the workingspace 20 in relative protection from dust and contamination. The workingspace 20 can be supplied with purge gas and/or operated at eitherslightly elevated pressures relative to ambient atmospheric pressure.

The upper portions of processing system 10 are sealed with respect tothe ambient environment and may be provided with an interface filterabove the interface section 14 and a processing filter above theprocessing section 16 to provide the requisite filtering of ambient airbefore it enters the processing area 20. These filter sectionspreferably employ HEPA type ultrafiltration filters. Air movingequipment, such as fans or the like forces air through the filters anddownwardly into the working space 20.

The processing system 10 also has a process station maintenance sectionand an instrumentation and control section that are separated from thework space 20 by portions of the frame 12. Since these sectionspotentially have higher contamination levels due to the presence andoperation of various equipment components associated with the processingstations, it is preferable to separate these sections from work space20. The processing system 10 is preferably mounted in a waferfabrication facility with clean room access to the front of theprocessor 15 and with gray room access to the maintenance section andthe instrumentation and control section rearward of the work space 20.Such gray rooms require fewer precautions against contamination thanclean rooms and, as such, they are less costly to build and maintain.The foregoing configuration thus reduces plant costs while allowingready access to portions of the process system 10 more typically needingmaintenance.

A front control panel 22 is disposed proximate the interface section 14and allows operator control. The control panel 22 is preferably a touchscreen cathode ray tube control display allowing finger contact to thedisplay screen to effect various control functions. A secondary controlpanel may be included in the control section and accessed from the grayroom so that operation can be effected from either front or back of themachine. All user programmable control functions and options arepreferably displayed upon the control panel to effect operation and setup of the processing system 10 by a user.

Semiconductor wafers 50 are supplied to and removed from the enclosedwork space 20 of processing system 10 through interface section 14. Thewafers are supplied to the interface section in industry standard wafercontainers or pods 51. The wafer containers are available from variousmanufacturers such as Empak, which sells a wafer container under thetrademark CAPSIL.

As best illustrated in FIGS. 5a and 5 b, the wafer container 51 has acover 52 which, when removed, allows semiconductor wafers to be insertedinto and removed from the wafer container. Typically, the cover 52 istranslucent to allow visual detection and optical scanning of the waferswithin the container 51. The wafer container 51 also includes a window54 to permit viewing and optical scanning of the wafers. On the sideopposite the window 54, the wafer container 51 is provided with featuresto facilitate handling of the wafer container 51 by automated equipment.These features include a set of inner circular slots 55, and a set ofouter circular slots 56. The manner in which the disclosed embodiment ofthe processing system 10 interacts with these features will be explainedin further detail hereafter. The wafer containers 51 are sealed and canbe supplied with purge gas. The number of wafers positioned within thecontainer 51 can vary, but at this time, the industry standard wafercontainers typically have a capacity for 13 to 25 wafers having adiameter of 300 mm.

In the disclosed embodiment, the interface section 14 functions as bothan input subassembly for receiving wafers to be processed, and an outputsubassembly for withdrawing processed wafers. Additionally, theinterface section 14 can provide a holding or inventorying capabilityfor both unprocessed and processed wafers. The interface section 14includes an input/output subassembly, generally indicated by the numeral30, which allows the wafer containers to be loaded into and removed fromthe processing system 10. The subassembly 30 is disposed in station 5 ofthe disclosed embodiment of the system 10.

The input/output subassembly includes an entry port, which iscontrollably opened and closed by the entry port door 32. The entry portdoor 32 may be pneumatically powered by an air cylinder 33 or the liketo slide upwardly and downwardly on a guide track 34 to open and closethe port. The components within the input/output subassembly 30 arepreferably operated so that they will not move until the entry port door32 is closed, thus enabling the port door to function as a safetymechanism for the operator.

When the entry port door 32 is opened, one or more wafer containers 51may be loaded onto a loading elevator 40 within container access station5. The loading elevator includes a container lift plate 42 which isadapted to receive a wafer container 51. In the disclosed embodiment,the container lift plate 42 is provided with coupling pins 44, which aremounted on the lift plate so that they are aligned and can be receivedwithin the respective inner slots 55 (FIG. 5b) provided on the industrystandard wafer containers 51. As shown, the portion of the lift plate 42between the coupling pins 24 is cut out, forming an almost pie-shapedcut-out 45. This cut-out portion 45 permits the wafer container 51 to betransferred to a loading plate 60, as will be described in furtherdetail below. To assist with the positioning of the wafer containerinner slots 55 onto the coupug pins 44 of the lift plate 42, the upperedge of the lift plate 42 is provided with at least one guide block 46.The lift plate 42 is carried on a guide track 47, and is raised to anoverhead position and lowered to a loading/unloading position adjacentthe entry port door 32 by operation of a pneumatic cylinder 48.

The loading elevator 40 allows the wafer containers to be loaded intothe processing system in different ways. When the lift plate 42 is inits lower position adjacent the entry port door 32, the wafer container51 can be loaded laterally onto the lift plate either via human loadingor automated robot loading. When the lift plate 42 is raised to itsoverhead position, loading can be accomplished vertically through anaccess door disposed through the top of station 5 through use of anoverhead transport system.

With the container lift plate 42 in its overhead position, a wafercontainer 51 can be loaded onto the loading plate 60 in the input/outputsubassembly. As show in FIG. 4, the loading plate 60 is provided withcoupling pins 62, similar to the coupling pins 44 of the lift plate 42,except that the coupling pins 62 on the loading plate are aligned withand adapted to be received by the outer slots 56 (FIG. 5b) on the wafercontainer. The loading plate 42 also includes at least one mountingblock 64 to assist in the positioning of the wafer container onto theloading plate. At its leading edge 65, the loading plate has apie-shaped projection 66 that is slightly smaller than and complementaryto the cut out portion 45 of the lifting plate. As best shown in FIG.5b, the cut-out portion 45 allows the loading plate 60 to translatethrough the lift plate 42 to transfer a wafer container from the liftplate to the load plate, or vice versa, as described in further detailbelow.

The loading plate 60 is mounted on a guide track 70 for transversehorizontal movement in the direction of arrows 71 relative to the entryport door 32. The horizontal drive mechanism is preferably comprised ofa motor drive and belt assembly 72, although other drive arrangementsmay be utilized. A second mounting and drive arrangement 75 mounts theloading plate 60 and includes various mounting arrangements and drivearrangements for moving the loading plate both vertically androtationally about a vertical axis. The mounting and drive arrangement75 include a drive arm 78 which is coupled via a mounting platearrangement to the loading plate 60. The drive arm 78 is preferablydriven vertically by a motor and lead screw drive arrangement 80 toraise and lower the loading plate 60. A motor and harmonic driveassembly 82 is coupled to the loading plate 60 to provide the rotationaldrive about a vertical axis 83. The motor and harmonic drive assembly 82rotates the loading plate 90°, from a position in which the leading edge65 of the loading plate is facing the entry port door 32, to a positionin which the leading edge 65 is facing the container inventorysubassembly 90 (see FIG. 1B). Each of the drive mechanisms preferablyincludes an incremental encoder to control the positioning of theloading plate 60 and an absolute encoder to determine the relativehorizontal, vertical, and rotational position of the loading plate 60.The drive mechanisms operate in combination to position the loadingplate 60 at the container inventory subassembly 90 (illustrated in FIG.1B) to permit the wafer containers 51 to be transferred to and from thecontainer inventory subassembly 90.

The loading plate 60 can either receive a wafer container 51 from anoperator through the entry port, or can receive a wafer container thathas been placed and temporarily stored on the lift plate 42 tofacilitate both input and output operation of the container accessstation 5. In order to transfer the wafer container from the lift plate42 to the loading plate 60, the lift plate 42 is lowered to itsload/unload position, and the loading plate 60 is rotated so that itsleading edge 65 is facing the entry port door 32. In this position, theloading plate 60 is below the lifting plate 42. The loading plate 60 maythen be raised so that the pie-shaped projection 66 of the loading platetranslates through the cut-out portion 45 of the lifting plate 42. Asbest shown in FIG. 5b, during this action, the coupling pins 62 on theloading plate engage the outer slots 56 on the wafer container 51, whilethe coupling pins 44 on the lifting plate are removed from the innerslots 55 on the wafer container, thus accomplishing a complete transferof the wafer container 51 to the loading plate 60. The loading plate 60can then be rotated 90° to transfer the wafer container 51 to theinventory subassembly 90.

Referring to FIG. 6, the inventory subassembly 90 includes a centralhorizontal hub 92 with a plurality of arms 94 radially extendingtherefrom. In the present embodiment, the number of arms is six,although other numbers of arms can be employed. Mounted on the end ofeach arm is a container carrier 96 having an upper and a lower shelf 97,98, respectively. A bearing and timing shaft arrangement 99 mounts eachcontainer carrier 96 to an arm 94. The bearing and timing shaftarrangement 99 may be coupled with a timing belt to insure that theupper and lower shelves 97, 98 of each container carrier 96 alwaysremain horizontal regardless of the relative position of the arms aboutthe central hub 92. Mounted on each arm 94 is a tension pivot assembly106 which functions to reduce any play in the timing system. The upperand lower shelves 97, 98 of each container carrier 96 include couplingpins 102 which are positioned on each shelf so that they are alignedwith the inner slots 55 on the standard wafer container 51.

A drive arrangement in the form of an indexer 104 with twelve presetindex positions rotates the arms 94 with their container carriers 96around the axis of the hub 92 from a preset loading position adjacentthe input/output subassembly to a preset container transfer position180° opposite the loading position. An absolute encoder 108 is mountedon the central hub 92 to detect the relative positions of the arms 94.

In normal operation, each of the shelves will have a wafer containermounted thereon (twelve altogether) to facilitate the continuousprocessing of a full complement of wafers without interruption. Theinventory subassembly 90 can, however, handle fewer than twelve wafercontainers 51 depending on the batch processing requirements of thesystem user.

Detectors, such as, for example, optical sensors, can be mounted infixed relationship with the frame 12 and positioned to optically scanthe semiconductors wafers within the wafer containers as the containersare rotated about the central hub 92. Preferably, such detectors areplaced at a location adjacent the interface between the input/outputsubassembly 30 and the container inventory subassembly 90, and at alocation adjacent the interface between the container inventorysubassembly 90 and a container docking subassembly 110. Such opticalscanning allows the processing system 10 to keep track of all wafers asthey are processed through the system.

In operation, the indexer 104 rotates the arms 94 until a shelf on oneof the container carriers 96 reaches a preset loading position adjacentthe input/output subassembly 30. A wafer container 51 may then betransferred from the loading plate 60 to the respective container shelfby moving the loading plate 60 until it is positioned above the shelf,rotating the loading plate until the inner slots 55 on the wafercontainer 51 are aligned with the coupling pins 102 on the shelf, andlowering the loading plate 60 so that the inner slots 55 are received bythe coupling pins 102. The loading plate 60 may then be rotated slightlyto clear it from the shelf and then withdrawn. To unload the wafercontainer 51 from the inventory subassembly 90 for processing, the armand the container shelf holding the wafer container 51 can be rotated180° about the hub so that the wafer container can be accessed by thecontainer docking subassembly 110 disposed in the container dockingstation 6.

As best illustrated in FIG. 2, the container docking subassembly 110includes a robotic conveyor 111 comprising a robotic arm 112 mounted ona carriage 114 for linear movement along a guided track 115. The roboticarm 112 of the disclosed embodiment has three jointed segments—a loweror first segment 116 mounted to the carriage 114, a middle or secondsegment 117 linked to the first segment via a timing belt arrangement orthe like, and an upper or third segment 118 linked to the secondsegment. This robotic arm construction enables the arm to move up, downand back and forth while occupying a minimum amount of space. The thirdsegment 118 has a horseshoe shaped appearance and permits the roboticarm to lift and separate the wafer container 51 from a container shelfwithin the container inventory subassembly 90. Coupling pins 122positioned on the third segment are adapted so that they may contact andbe received within the outer set of slots 56 on the wafer container 51to complete the transfer to the robotic arm 112.

The carriage 114, together with the robotic arm 112, slide along theguided track 115 to a position adjacent to a container transfersubassembly, generally indicated at numeral 150. As illustrated in FIG.7, the container transfer subassembly includes a docking plate 152mounted on a linear slide 154 for movement in the direction of arrows151. Coupling pins 156 are positioned on the docking plate 152 so as toalign with the inner slots 55 on the wafer container 51. The dockingplate 152 also includes an aperture 158 for receiving a latch hook 160which is sized and adapted to latch into a groove or the like located onthe door of the wafer container 51. The latch hook 160 may be mounted ona pneumatic slide which permits the latch hook to move towards and awayfrom the wafer container 51 to latch and unlatch the wafer container 51.Roller guides 164 are provided on the latch hook 160 to facilitatecontact and engagement of the latch hook with the wafer container. Anoverhead frame 166, mounted to the docking plate 152, houses sensors fordetecting the presence of wafers within the wafer container. Anothersensor, such as a fiber optic cable, may be used to detect the presenceof a wafer container on the docking plate.

The linear slide arrangement 154 slides the docking plate 152 into aposition adjacent a hatch interface, generally indicated by numeral 180in FIGS. 1B, 8A and 8B. The hatch interface 180 is disposed in the wafertransfer station 8. Referring now to FIGS. 8A and 8B, the hatchinterface 180 includes a hatch cover 182 which supports an interfaceplate 184 that is sized and adapted for sealing engagement with the doorof the wafer container 51 The interface plate supports a perimeter seal186 which seals the interface plate 184 with the wafer container door.

Vacuum cups 188 fit through apertures 190 in the interface plate to makevacuum sealing contact with the wafer container door and secure the doorto the interface plate. T-shaped locking keys also extend throughapertures in the interface plate and insert into receptors in the wafercontainer door. A rotary actuator 194 turns the locking keys to lock thewafer container door into sealing engagement with the interface plate.In the event of a loss of vacuum through the vacuum cups 188, theT-shaped keys help to retain the container door against the interfaceplate 184. The hatch cover 182 and interface plate 184 are mounted to apneumatic cylinder assembly 196, comprised of cylinder assemblies 196 aand 196 b, which allow the hatch cover and interface plate to slideforward and backward, and up and down, relative to the wafer container.

In operation, vacuum is applied to the vacuum cups 188 so that thecontainer door is held in vacuum sealing relationship with the interfaceplate 184. The vacuum seat traps any contaminants that might be on thecontainer door and prevents them from entering into the processingsection. The actuator 194 turns the keys to lock the container door tothe interface plate. The pneumatic cylinder assembly 196 a slides theinterface plate 184 and hatch cover 182 backwards (i.e. away from thecontainer), causing the container door to move with the interface plate.This opens the container and exposes the interior of the container tothe clean environment of the processing section. The pneumatic cylinderassemblies 196 a and 196 b then cooperate together to slide theinterface plate 184 and the hatch cover 182, together with the containerdoor, downward, and then forward (i.e. toward the container) to move thedoor out of the way for handling and processing of the wafers.

In a preferred embodiment, the processing system is provided with twocontainer transfer subassemblies 150, and two hatch interfaces 180, asgenerally illustrated in FIG. 2, that are disposed within and proximateto the container docking station 7. This allows one container transfersubassembly 150 to handle wafer containers 51 holding unprocessedwafers, while the other subassembly 150 handles containers 51 holdingprocessed wafers, thus permitting efficient handling of the wafers.

The wafers are removed from the container 51 by a wafer transfersubassembly 200 disposed in the wafer transfer station 9. The wafertransfer subassembly 200 includes a wafer comb 202 (see FIGS. 9a and 9b) mounted on a carriage assembly 230. (See FIG. 10). Referring now toFIGS. 9a and 9 b, the wafer comb 202 comprises an outer comb frame 204having outwardly extending engagement arms 208, each of which carries aset of teeth 210 at the outer end thereof. The middle portion of theouter comb frame also carries a middle set of teeth 212. Acomplementary-shaped inner comb frame 214 has an outer set of teeth 220mounted on the outer ends of each of its engagement arms 218 and amiddle set of teeth 222 mounted on the middle portion of the frame. Theinner comb frame is positioned adjacent the outer comb frame such thatthe middle set of teeth 212 on the outer comb frame extend through anopening 224 in the inner comb frame, and the outer and middle sets ofteeth 220, 222, respectively on the inner comb frame are adjacent thecorresponding sets of teeth on the outer comb frame.

The outer comb frame 204 is slideable vertically with respect to theinner comb frame 214. The inner comb frame 214 is in fixed positionalalignment with the carriage assembly 230. When the outer comb frame isin its lowest position, the teeth on the outer comb frame are alignedwith the teeth on the inner comb frame in an “open” wafer comb position.In this position, the wafer comb 202 can be inserted into the open wafercontainer until the teeth of the wafer comb are interleaved with thewafers in the container. The wafers are held within the wafer comb byslightly lifting the outer comb frame 204 to the “closed” wafer combposition illustrated in FIGS. 9a and 9 b. Various mechanisms, such as alead screw driven by a stepper motor, can be used to actuate lifting ofthe outer comb frame 204. In this closed position, the teeth on theouter comb frame are offset with respect to the teeth on the inner combframe, causing the wafers to be cantilevered on the outer comb frameteeth. The wafer comb is designed such that the individual teeth arecanted down at a slight angle from horizontal, such as a 10 mm, pitch,to insure that the wafers remain positioned within the wafer comb.

To insure proper positioning of the wafers within the wafer comb, it maybe desirable to provide the wafer comb with sensors. In one embodiment,sensors 226 are provided at each tooth of the middle set of teeth 212 onthe outer comb frame 204.

The carriage assembly 230 which mounts the wafer comb 202 is itselfmounted on a guide track 232 for linear movement toward and away fromthe open wafer container 51. The carriage assembly 230 includes a rotarydrive mechanism 234, such as a rotary motor 236 and harmonic drive 238,for rotating the wafer comb 90° about a horizontal axis, from ahorizontal position, to a vertical position, best shown in FIG. 2. Thecarriage assembly 230 also includes a vertical drive mechanism 240 forlifting the wafer comb so that the wafer comb can deposit the wafersonto a wafer support in the form of a wafer bunching comb 250 (see FIG.2).

Referring to FIGS. 11A and B, the wafer bunching comb 250 has an uppersurface 252 on which is provided a series of wafer-receiving grooves254. Each of the grooves has downwardly converging receiver sides 256which adjoin a relatively narrow slot section 258. The slot section hassubstantially parallel side walls and is sized to provide a width about0-10% greater than the thickness of the wafers being received therein.The receiver sides help to insure proper insertion of the wafers withinthe grooves while minimizing contact with the wafer surface. The uppersurface 252 and the slot sections therein are dimensioned to form an arcthat generally corresponds to a segment of the diameter of the wafer.The particular number of grooves in the wafer bunching comb may vary.Typically there will be 26 to 50 grooves in order to correspond with thecapacity of two of the associated wafer containers being used, so thatthe wafers from two wafer containers can be processed at once. Sensors260 are provided on the upper surface 252 to detect the properpositioning of the wafers within the grooves.

The wafer bunching comb 250 has a longitudinal slot 262 that is sized topermit the vertical drive assembly 240 (see FIG. 10) of the wafer combto pass therethrough. The vertical drive assembly 240 can lift the wafercomb until it is slightly higher than the wafer bunching comb 250, andthe horizontal drive assembly can linearly move the wafer comb until thevertical drive assembly is positioned within the longitudinal slot andthe wafers are aligned with the grooves in the wafer bunching comb 250.The wafers can then be lowered in a controlled fashion into the groovesin the wafer bunching comb.

Once the wafers are in place in the wafer bunching comb 250, the dockingassembly steps can be reversed so that the container door can bereplaced onto the wafer container, the wafer container can then beretracted from the interface plate, and placed back onto a wafercontainer shelf of the inventory subassembly. The entire docking andwafer transfer processes can then be repeated so that the wafers fromtwo wafer containers are positioned on the wafer bunching comb 250.

FIGS. 1B, 1C, and 2 show a robotic conveyor, generally indicated by thenumeral 280, for conveying the wafers within the processing system,specifically between, to and from the bunching comb 250 and one or moreprocessing stations, such as processing stations 290. The roboticconveyor 280 includes a mounting beam or rail 282 upon which a movableconveyor robot subassembly 284 is mounted and moves relative to therail.

The robotic device can be of various designs. In one design, the roboticconveyor comprises an articulated arm having an upper arm portion 285, alower arm portion 286, and a hand portion 287. Mounted to the handportion is an engagement toot 288 for engaging the semiconductor wafersand delivering them to various individual or plural work stations.Further details of suitable conveyor devices and other aspects of theprocessing system are described in U.S. Pat. No. 5,544,421, issued Aug.13, 1996; U.S. Pat. No. 5,660,517 issued Aug. 26, 1997; and U.S. Pat.No. 5,664,337, issued Sep. 9, 1997, each of which is herein incorporatedby reference.

FIG. 1C illustrates flow of semiconductor wafers as they are processedby the processor 10. As illustrated, the pods 51 are first place in theinsertion station 5. The components of the insertion station 5 rotatethe pod 51 and place it on the inventory subassembly 90 of the inventorystation 6 where they remain until such time as the wafers containedtherein are to be processed. When the wafers of a pod 51 are to beprocessed, the respective pod 51 is removed from the inventorysubassembly 90 by one of the docking assemblies 150. The dockingsubassembly 150 transports the pod to the hatch interface where thewafers are removed from the pod without being exposed to the ambientatmospheric conditions of the interface section. Rather, the wafers areonly exposed to the clean environment of the workspace area 20. Afterextraction, the wafers are presented to the wafer conveying system 280which transports them for processing in the appropriate processingstation(s) 290. After removal from the processing station(s), the wafersare returned to the same or different pod and the pod is sealed withoutexposing the wafers to the ambient atmospheric conditions of theinterface section. The respective docking subassembly 150 then returnsthe pod containing the processed wafers to the inventory subassembly 90where the pod is stored until such a time as the wafers therein are toundergo further processing within the work space 20 or until they areremoved through station 5 by an operator as directed, for example,through control panel 22.

The processing section of the processing system includes at least oneand preferably a plurality of individual processing stations 290 whichcan be of various construction. Further details with respect to suitableprocessions stations, and more specific explanation about the loading(installing) and unloading of the wafers into the processing stationsare described in U.S. Pat. No. 5,664,337, issued Sep. 9, 1997, which isherein incorporated by reference.

Referring to FIGS. 12 through 15, each processing station 290 includes aprocessing vessel 292 which partially encloses a processing bowl. Theprocessing vessel also mates with a movable door 512 which can be movedbetween the closed position shown in FIG. 12, and a retracted positionshown in phantom outline. The disclosed embodiment of the processingsystem 10 includes an improved door assembly 500 for the processingvessel.

Referring to FIGS. 12 and 13, the door assembly 500 is in fixedpositional alignment with a front wall 502 of a processing vessel. Thefront wall 502 is provided with an access opening, defined here by acircular opening 506 of the front wall (best illustrated in FIG. 15).When the front wall 502 is mounted to the remaining portions of theprocessor, the opening periphery 506 is positioned to be in alignmentwith an access opening 507 (See FIG. 15) formed in the front wall of theprocessor bowl 294.

The door assembly 500 further includes a door support plate 510 whichmounts a door 512 and a door extension and retraction operator 514. Thedoor 512 includes a stiffening plate 504 and a viewing window 508 thatpermits visual inspection of the processing chamber defined by the bowl294. The door extension and retraction operator 514 of the disclosedembodiment includes a stationary outer cylinder 516 coupled to the doorsupport plate 510, and an operative extension part 518. The operativeextension part 518 is concentrically positioned inside of the outercylinder 516 for controllable extension and retraction relative to theouter cylinder. Additional features and the operation of the doorextension and retraction operator 514 are discussed in greater detailbelow.

The door support plate 510 includes a viewing aperture 520 for providingvisibility through the window 506 into the processing chamber containedwithin the bowl 294 of the processor. The door support plate 510 iscoupled on each side to slideable guide brackets 522 using, for example,conventional fasteners. Each slideable guide bracket 522 is slideablymounted to a respective pneumatic band cylinder 524. The band cylinders524 are connected to the front wall 502 of the processing vessel viamounting plates 528. The combination of the guide brackets 522, the bandcylinders 524, and the mounting plates 528 provides a simplified andrigid door mounting construction that needs no additional guides orsupport blocks. The guide brackets 522 are mounted for substantiallyvertical movement so that the door assembly can be moved between an openor fully displaced position to allow access into the bowl of theprocessor, and a closed position wherein the door assembly is insubstantially concentric alignment with the access opening. In theclosed position, the door can be extended into the access opening andsealed against the bowl of the processor.

Referring to FIGS. 14 and 15, which show sectional views of the doorassembly 500, the movement of the extension part 518 relative to theouter cylinder 516 is explained in greater detail. To this end, anannular inner stationary cylinder 530 has an annular flange portion 532and an axially extending ring portion 534. The annular flange portion532 is securely mounted on its outer side upon the door support plate510. At the point of mounting, the annular flange portion is bounded onits opposite side by the outer cylinder 516. A plurality of fastenerssecure the outer cylinder 516 and the annular flange portion 532 to themounting plate 510.

The extension part 518 is concentrically positioned between the innercylinder ring 530 and the outer cylinder 516, and includes a U-shapedportion 519 that defines an annular guide receptacle 520. As illustratedin FIG. 14, the axially extending ring portion 534 fits within theannular guide receptacle 520. The extension part 518 also includes anannular piston portion 540. The annular piston portion 540 rides withinan annular piston operation chamber 542 defined by the ring portion 534and the outer cylinder 516.

The piston 540 bifurcates the piston operation chamber 542 into twooperative compartments: a retraction chamber compartment 543 and anextension chamber compartment 544. Each piston chamber compartment isadapted to hold pneumatic or hydraulic fluid. Multiple annular seals 550are positioned about the piston 540 and the extension part 518 to sealseparate fluid within the chambers 543 and 544.

Separate fluid supply conduits are preferably provided to the retractionchamber 543 and the extension chamber 544 to increase or decrease fluidpressure within the respective chambers and effectuate movement of thepiston. As shown in FIG. 15, when hydraulic fluid is supplied under anincreased pressure to the extension chamber 544, a pressure differentialis created on the piston 540 which will cause the extension part 518 toextend away from the door support plate. Movement of the extension part518 and the integral piston 540 into the extended position shown in FIG.15 moves the door into sealing engagement with the access opening 506formed in the front wall 502 of the processor bowl, thereby closing thesemiconductor processor. Mounted on the periphery of the door 512 is anannular door seal 551. Preferably, the door seal is formed of Teflonusing known machining techniques. The door seal includes an axiallyextending shroud portion 552 and an annular tongue portion 554. When thedoor is in the closed position shown in FIG. 15, the shroud portion 552of the door seal lies in a plane that is within the front wall of theprocessor, and the tongue portion presses in sealing engagement againstthe outside rim of the processor bowl, thereby effectuating a sealbetween the door and the processor bowl. The door seal also preferablyincludes a flange portion 555 which acts as a stop for the door seal.

The combination of the piston 540 and the door seal 550 provides ahighly reliable and effective door closing and sealing mechanism.Movement of the piston allows the extension part to move the dooroutwardly from the support plate equidistantly at all times without theneed for peripheral adjustments to ensure equidistant movement. Byseating against the outside rim of the processor bowl, the tongueportion provides an effective fluid tight seal and automaticallycompensates for any misalignment between the door and the processor.

Numerous modifications may be made to the foregoing system withoutdeparting from the basic teachings thereof. Although the presentinvention has been described in substantial detail with reference to oneor more specific embodiments, those of skill in the art will recognizethat changes made thereto without departing from the scope and spirit ofthe invention as set forth in the appended claims.

What is claimed is:
 1. A processing system for processing wafers provided with a container having a removable container door, comprising: a wall; a container holding position on a first side of the wall, for holding a container; a wafer transfer robot on a second side of the wall; an opening in the wall; a cover adapted to cover the opening in the wall; a container door holder associated with the cover for engaging and holding a container door; a cover actuator assembly, for moving the cover and a container door to and away from the opening in the wall; at least one centrifugal liquid spray process chamber; and one or more robotic conveyors for moving the wafers into and out of the centrifugal liquid spray process chamber.
 2. The system of claim 1 further comprising a docking plate at the container holding position, with the docking plate moveable toward and away from the wall to dock and undock a container.
 3. The system of claim 1 wherein the transfer robot comprises a comb having equally spaced apart fingers for handling a batch of horizontally oriented wafers.
 4. The system of claim 3 where the comb is moveable through the opening in the wall and into and out of the container, to move wafers into and out of the container and into the transfer station.
 5. A system for processing the wafers in a clean environment, comprising: an enclosure; a process section and a transfer section within the enclosure; a docking station adjacent to the transfer section, with the docking station including a wall having at least one opening; a cover for covering the opening in the wall; a cover actuator attached to the cover, for moving the cover to and away from the opening in the wall; a wafer transfer device within the enclosure and movable through the opening in the wall, when the cover is removed from the opening, for removing the wafers from the container, with the wafers in a horizontal orientation; at least one centrifugal liquid spray process chamber wherein the wafers are rotated about a vertical axis; and a robot moveable within the enclosure for moving the wafers into and out of the centrifugal liquid spray process chamber.
 6. The system of claim 5 further comprising an interface plate attached to the cover, and a key and a container door holder extending outwardly from the interface plate, to engage a container door.
 7. The system of claim 6 wherein the cover actuator is adapted to move the cover and a container door to a position vertically below the opening.
 8. A system for processing semiconductor wafers, comprising: an enclosure; a transfer section and a process section in the enclosure; a docking station separated from the transfer section by a wall having at least one opening, to allow movement of wafers from the docking station into the transfer section; a cover for covering the opening in the wall; at least one door release actuator associated with the cover for releasing and holding a door of a container; a cover actuator linked to the cover, with the cover actuator adapted for moving the cover and a container door from a first position, where the cover is over the opening, to a second position, below the opening; at least one centrifugal liquid spray process chamber within the chamber; and a robotic conveyor for moving the wafers into and out of the centrifugal liquid spray process chamber.
 9. The processing system of claim 8 further including an electronic controller for controlling the door release actuator, the cover actuator and the robot.
 10. The processing system of claim 9 further including at least one optical sensor for sensing wafers within the container, with the optical sensor connecting to the controller.
 11. A processing system for processing wafers provided with a container having a container door, comprising: a wall; a container position on a first side of the wall, for holding a container containing a batch of wafers in a horizontal orientation; an opening in the wall; a cover adapted to cover the opening in the wall; container door holding means for engaging and holding a container door; cover actuator means for moving the cover and a container door to and away from the opening in the wall; at least one centrifugal liquid spray process chamber; and robotic conveyor means for removing the wafers from the container, reorienting the wafers from a horizontal to a vertical position, and for placing the wafers into the centrifugal liquid spray process chamber.
 12. The system of claim 11 wherein the robotic conveyor means comprises a first robot having a comb moveable into a container, for picking up a batch of horizontal wafers, and a second robot for moving the wafers in a vertical position into the centrifugal liquid spray process chamber. 